The present invention relates to a coffee maker for forcing a stream of hot water from a hot water boiler through ground coffee beans to brew a pot of coffee.
For brewing a pot of rich-flavor or tasty coffee, a spoonful of ground coffee beans are steamed and expanded by hot water for ease of brewing and then soaked intermittently with flows of hot water. Such coffee makers having a function of steaming and a function of supplying intermittent flows of hot water at a lower cost are disclosed in Japanese Patent Laid-open Nos. 58-143722 and 6-284971. Those conventional coffee makers are equipped with a hot water reservoir for intermittently feeding a coffee brewing chamber with hot water by the action of siphoning.
However, the siphoning action in such a conventional maker may be interrupted during the brewing of coffee due to an increase of the inner pressure in the hot water reservoir, an unstable exchange of the internal air with fresh air at the siphon system, a resistance in the flow of air at the air-intake, and a dislocation of the supply of hot water from the hot water boiler. Thus, the siphoning cannot easily be carried out at given intervals of time. When the hot water is supplied continuously, it can rarely brew a pot of tasty coffee.
More specifically, as shown in FIG. 29, the intermittent siphoning action largely depends on the intaking of air from a hot water spout 2 into a hot water reservoir 1 when the stored hot water has been released from the reservoir 1. This action requires a space 4 between the bottom of the hot water reservoir 1 and the siphon system 3 for exchanging the air. Accordingly, a pool of water may remain in the space 4 at the bottom of the hot water reservoir 1 as being not affected by the siphoning action. Also, a remaining steam generated by a hot water boiler 5 may be cooled and condensed to water after the brewing and stay in the hot water reservoir 1.
For solving the above described drawbacks, a modification of the coffee maker is disclosed in Japanese Utility-model Laid-open No. 59-73232, which discloses that a valve in the bottom of the hot water reservoir for drainage. It however has a complicated construction and permits a coffee brewing section to be dismounted/mounted with much difficulty.
When hot water is supplied from the hot water boiler 5 to the hot water reservoir 1 in a fast manner, it may interrupt the exchange of air between the hot water reservoir 1 and the siphon system 3 at a hot water receiver 8 in a dripping unit 7 above the coffee brewing chamber 6. As a result, the balance between the supply of hot water from the hot water boiler 5 and the transfer of hot water from the hot water reservoir 1 to the hot water receiver 8 is fractured. That hence causes the hot water to be supplied continuously but not intermittently.
For brewing a pot of coffee while stably carrying out the siphoning action, the maker needs to have an air vent 9 in the top of the hot water reservoir 1 which inhibits the inner pressure from excessively increasing in the hot water reservoir 1. As the hot water reservoir 1 is nearly filled up with hot water, the air vent 9 permits a jet of steam or hot water itself to blow out from the reservoir.
Alternatively, in another conventional coffee maker with a heater 12 an increased output for shortening the brewing period or elevating the brewing temperature, as shown in FIG. 30, the temperature of the heater 12 may soar up as a water tank 11 becomes nearly exhausted or feeds a less flow of water. Accordingly, the water is more evaporated than boiled and finally escapes in the form of steam from a dripping spout 14.
When the tank 11 becomes completely empty, and when the heater 12 and a water feed system including a pump-up pipe 13 are heated up, the temperature of remaining water in the coffee maker increases so as to evaporate it. This causes the temperature of the heater 12 to increase for a while even when the electricity is disconnected by a thermostat 15 or the like. The greater the output of the heater 12, the higher the temperature remains. In particular, the temperature of a connector tube 16 for connecting between the heater 12 and the pump-up pipe 13 becomes very high. A selection of the material of the connector tube 16 is limited in view of the heat resistance.
Under a low ambient temperature, the temperature of the hot water passes through cool ground coffee beans and is dripped into a glass decanter 17 at which the temperature is also low. Thus, the temperature of the water may decline. For increasing the temperature of brewed coffee, the glass decanter 17 filled with the brewed coffee has to be heated with a keep-warm plate 18. This requires the heater 2 to lower its output, thus extending the brewing time. As the hot water runs slowly through the ground coffee beans, resultant brewed coffee becomes strong.
When all the water stored in the tank 11 has been dripped from the dripping spout 14 into a basket 19 filled with the ground coffee beans, the heater 12 is turned off, and a notifying section releases a notice of the end of the brewing action. As the basket 19 slowly delivers the brewed coffee, the notice will be released on the way of the brewing.
A coffee maker capable of removing remaining water from a hot water reservoir after the coffee brewing action and delivering the hot water intermittently to a coffee brewing chamber where it is scattered over ground coffee beans is provided to brew tasty flavor coffee using a simple arrangement.
Another coffee maker is also provided. The maker has an air vent for inhibiting the inner pressure in the hot water reservoir from increasing excessively, whereby hot water or steam hardly leaks or splashes out from the hot water reservoir during service.
While the temperature of a heating device for generating hot water and a water feed system is controlled to stay not very high, the output of the heating device is optimized for brewing coffee. The resultant brewed coffee has improved flavor and taste and is kept favorably hot.
A coffee maker includes a hot water reservoir having a hot water reservoir bottom (referred to as a reservoir bottom hereinafter) and a hot water reservoir enclosure (referred to as a reservoir enclosure hereinafter). The maker further includes a tube for delivering hot water to a coffee brewing chamber in the reservoir bottom, and a cap disposed over and spaced from the tube by a specific distance. The distance between the cap and the tube is not greater than the maximum inner diameter of an opening of the tube to develop a siphoning effect for delivering the hot water intermittently to the coffee brewing chamber. This allows the hot water and the air to flow alternately above the opening of the tube, hence making the intermittent hot water delivering action stable.
A further coffee maker includes a hot water reservoir for storing hot water, an intermittent hot water delivering section for delivering the hot water intermittently from an outlet of the hot water reservoir to the outside, and a water treating unit mounted detachably to the hot water reservoir for purifying the hot water received from the outlet. The hot water reservoir has a bottom opening provided at the bottom thereof. The water treating unit is equipped with a lid. When the water treating unit is installed from below to the hot water reservoir, the lid shuts the bottom opening of the hot water reservoir. As the bottom opening closes with the lid on the water treating unit, the intermittent hot water delivering action is hardly interrupted. Once the water treating unit is dismounted, the bottom opening opens widely. Accordingly, while remaining water in the water treating unit is removed, the hot water reservoir is simultaneously drained from the bottom opening.
A still further coffee maker includes a hot water reservoir having an intermittent hot water delivering section for delivering hot water not intermittently to a coffee brewing chamber. The hot water reservoir has an air vent thereof extending downwardly of the hot water reservoir. This inhibits hot water or steam from leaking and splashing out from the hot water reservoir in upper and side directions after the hot water is completed to supply to the hot water reservoir.
A still further coffee maker includes a heating device for heating up water received from a water tank, a heater controller for controlling the heating device, and a temperature sensor for detecting the temperature of the heating device or the water feed system. When the temperature measured by the temperature sensor increases to a first setting degree during the coffee brewing action, the heater controller declines the output of the heating device and continues to energize the device. When the water is nearly exhausted, and when the temperature of the heating device soars up at the end of the brewing action to change the hot water into steam, the output of the heating device declines. As a result, the release of steam is reduced. The output of the heating device during the brewing action is favorably controlled to an optimum level for brewing coffee.